RF23 | PSAT240 Suboptimal Thyroid Hormone Replacement is Associated with Worse Hospital Outcomes

INTRODUCTION: Many patients in the US with hypothyroidism receive suboptimal treatment with thyroid hormone. Sustained off-target TSH levels have been shown to cause serious harm to patients, including increased risk of cardiovascular disease and excess mortality over time. Suboptimal treatment may also impact hospital outcomes. The primary objective of the study was to identify differences in hospital outcomes between patients with and without hypothyroidism. METHODS: This is a retrospective cohort study that utilized the propensity score-based fine stratification method to balance covariates. Patient data was extracted from a large, US-based, IBM MarketScan® Commercial Claims and Encounters Database from January 1, 2008 to December 31, 2015. Participants included patients 64 years and younger who had commercial insurance and a thyrotropin (TSH) level collected prior to a medical or surgical hospital admission. Covariates included age, sex, US region, type of admission (medical vs surgical), year of admission, and co-morbidities. The primary exposure was defined as clinical hypothyroidism, which was divided into 4 subgroups based on pre-hospitalization TSH level: low (TSH <0.40 mIU/L), normal (TSH 0.40–4.50 mIU/L), intermediate (TSH 4.51–10.00 mIU/L), and high (TSH >10.00 mIU/L). Non-hypothyroidism was the non-exposure (control). The primary outcomes were length of stay (LOS), in-hospital mortality, and readmission outcomes following medical and surgical admission. RESULTS: A total of 46,235 patients were included in the final study population, of whom 9,394 had a diagnosis of hypothyroidism. Those with a high pre-hospitalization TSH level had a LOS that was 1.2 days longer (95% CI [1.1–1.3]; p = 0.001), a 41% higher risk of 30-day readmission (RR 1.41, 95% CI [1.13–1.75]; p = 0.002), and 33% higher rate of 90-day readmission (RR 1.33, 95% CI [1.13–1.56]; p <0.001) compared to balanced controls. Patients with intermediate TSH levels exhibited increased likelihood of 30-day readmission (RR 1.20, 95% CI [1.01–1.43]; p = 0.04). Conversely, those with a normal pre-hospitalization TSH level had a decreased risk of in-hospital mortality (RR 0.55, 95% CI [0.34–0.89]; p = 0.02) and 90-day readmission (RR 0.91, 95% CI [0.85–0.99]; p = 0.02). CONCLUSIONS: Suboptimal treatment of hypothyroidism appears to be associated with worse hospital outcomes, including longer LOS and higher rate of readmission. Public health strategies designed to deliver appropriate, consistent outpatient treatment of hypothyroidism are needed to improve hospital outcomes in those patients with off-target TSH levels. Presentation: Saturday, June 11, 2022 1:00 p.m. - 3:00 p.m., Sunday, June 12, 2022 12:30 p.m. - 12:35 p.m.